Interpretive Handbook

Test
8909 :
Nitrogen, Total, Feces

Nitrogen is a key component of proteins. During protein catabolism (proteolysis), nitrogen is excreted in the urine and feces. Protein catabolism may be increased after stress (eg, physical trauma, surgery, infections, burns).

"Nitrogen balance" is the difference between the amount of nitrogen ingested and the amount excreted. A patient who is in negative nitrogen balance is using muscle protein to meet the metabolic requirements of the body and is, therefore, in a catabolic state.

Average fecal nitrogen excretion is approximately 2 g/day, but fecal nitrogen excretion is highly variable, especially in conditions resulting in excessive protein catabolism. Significantly abnormal excretion rates, resulting in negative nitrogen balance, may be associated with severe stress due to multiple trauma, head injury, sepsis, or extensive burns. Elevated values >2.5 g total fecal nitrogen/24 hours are usually found in cases of chronic progressive pancreatitis. The goal with therapy for a depleted person is a positive nitrogen balance of 4 to 6 g nitrogen/24-hours.